Swedish police published a photo of an alleged truck driver, who was on the run after he rammed the vehicle over people. The picture was released by Swedish Security Service SAPO, according to Swedish Television.

The police said they have launched a manhunt, but did not know if this was an isolated incident or whether more could be expected.

Currently, Swedish National Rail company said that all trains to and from Stockholm Central Station have been cancelled.

Additionally, several lanes on the Oresund Bridge, connecting the Danish capital Copenhagen and the southern Swedish city of Malmo, have been shut down at the police request.

"So we have only two lanes for cars open in the direction of Denmark for the police to be able to control," police spokesperson Sanna Holmqvist told Swedish Television (SVT).

In Malmo, the police are now looking through and checking the trains on the way to Denmark, according to SVT.

All traffic around the Stockholm city, including subway and train, has been closed after the attack. Traffic barriers were put in place in many parts of Stockholm. Police have also urged people not to move to the Old Town, saying the people at the south part of the city should stay indoors.

Currently, the crime scene and the area around the Central Station in the centre of Stockholm is still cordoned off.

Many people in Stockholm's city centre were still trapped and remained in their offices or shops after the attack. The police would not give any clear recommendations about whether people should go home or stay.

Five different premises will be opened for those who are in the centre of Stockholm and can not go home because of the stopped underground traffic, wrote the Stockholm City on its website.